Fluid pressure starting and shutdown system for engines



Aug. 4, 1964 E. B. FOX 3,143,105

FLUID PRESSURE STARTING AND SHUTDOWN SYSTEM FOR ENGINES Filed Jan. 22, 1962 3 Sheets-Sheet 1 BIG--J...

INVENTOR. ELTON B. FOX

' ATTORNEY Aug. 4, 1964 5, ox 3,143,105

FLUID PRESSURE STARTING AND SHUTDQWN SYSTEM FOR ENGINES Filed Jan. 22, 1962 3 Sheets-Sheet 2 EIEI 3 6! INVENTOR. ELTON B. FO

ATTORNEY Aug.4,1964 E.B.FOX 3J43J05 FLUID PRESSURE STARTING AND SHUTDOWN SYSTEM FOR ENGINES Filed Jan. 22. 1962 s Sheets-Sheet a a J 3i 78 INVENTOR ELTON 5, FOX IE I l:'- 5 fin ATTURNEY United States Patent 3,143,1495 FLUID PRESSURE STARTENG AND SHUTDUWN SYSTEM Ffili ENGINES Elton B. Fox, 618 36th St, Richmond, Calif. Filed Jan. 22, 1962, Ser. No. 167,549 6 Claims. (Cl. Eli-47%) The invention relates to devices associated with internal combustion engines for automatically starting and shutting down of the engine.

An object of the present invention is to provide an all pneumatic control which is connected to and correlated with the operation of the engine to be controlled and which functions automatically to shut oif the supply of engine starting air when the engine starts and to shut off the engine under pro-determined over speed operating conditions.

Another object of the present invention is to provide a single unitary control structure which will perform both of the aforementioned control functions and do so with sensitivity, precision and unfailing reliability.

The invention possesses other objects and features of advantage, some of which of the foregoing will be set forth in the following description of the preferred form of the invention which is illustrated in the drawings accompanying and forming part of this specification. it is to be understood however, that variations in the showing made by the said drawings and description may be adopted within the scope of the invention as set forth in the claims.

Referring to said drawings (three sheets):

FIGURE 1 is a diagrammatic representation of an engine starting and stopping control system constructed in accordance with the present invention and shown in operative association with the engine to be controlled.

FIGURE 2 is. a cross-sectional view of the main control unit taken substantially on the plane of line 2-2 of FIGURE 1.

FIGURE 3 is a cross-sectional view of the control unit taken substantially on the plane of line 33 of FIG- URE 2.

FIGURE 4 is a cross-sectional view of the unit taken substantially on the plane of line 44 of FIGURE 3.

FIGURE 5 is a cross-sectional view of the unit taken substantially on the plane of line S-5 of FIGURE 4.

The control system of the present invention is adapted for use with an internal combustion engine which has associated therewith a pneumatic starting means such as air motor 7, and a stopping means such as the displaceable engine shut-off arm 8 associated with the fuel supply device 9 for the engine. As will be understood, engines may be started pneumatically by an air starting motor as here shown usually connected to a starting gear on the fly wheel of the engine, or air may be injected under pressure directly into the cylinders to effect reciprocation of the engine. The present control system works equally well with either type of starting and functions by the supply of starting air through conduit 11 here shown connected to air motor 7. Similarly, engines may be shut down by cutting oil? the fuel supply or, in some cases, shorting the ignition. Either carburator or fuel injection may be used to control the fuel supply and the present system is equally applicable to all types of engine shutdown devices, the displacement of arm 8 merely being taken here as a typical operation for controlling one of the well known engine shutdown devices. Important, however, is the fact that the engine shutdown device is in the present system pressure responsive, and this is accomplished by a pressure responsive control unit 12 connected by rod 13 to arm 8; and the supply of engine starting air to conduit 11 is similarly under the control of a pressure responsive valve 14. Thus, by the.

use of control air pressure supplied in the present instance by conduit 16 to shut-01f device 12 and by conduit 17 to the pressure responsive air valve 14; and in accordance with the present invention the supply of such control air in lines 16 and 17 is under the control of an engine speed responsive valve unit which is connected, as by belt 19 to the engine and can therefore sense the starting up of the engine and also its over speeding. This sensing is accomplished by a governor assembly 21, see FIGURE 2, which drives or displaces as a function of engine speed, a multiple position valve means, as shown in FIGURE 3. As will be further seen from FIGURE 1, the system is connected to a main pressure source by conduit 22 which connects by conduit 23 to the intake side 24 of the pressure responsive valve 14 and to the high pressure side of a pressure reducer 26 which supplies at conduit 27 relatively low pressure air to the control system. For example, relatively high air pressure is desired for engine starting usually in the order of pounds per square inch for a starting motor and up to about 250 pounds per square inch and more for cylinder injection. On the other hand, a much lower pressure in the order of 50 pounds per square inch is quite satisfactory for use in the control system and simplifies the design and construction of valve parts.

Initiation of engine operation is here efiected by an engine starting valve 28, which may be manually or automatically operated and which is connected to air supply conduit 27 and is connected by conduit 29 to the engine speed responsive valve unit 13 which in turn provides for the continuation of flow of control air through conduit 17 to the pressure responsive valve 14 when the engine is not running, the unit 18 functioning in accordance with the present invention to shut off such control air when the engine starts.

Unit 12 is here cocked to an engine run position and is triggered for resilient displacement to shut-off position by a decrease in air pressure received at unit 12 through conduit 16. Valve means 18 is so arranged that such an air pressure decrease will be effected only when engine 6 over speeds.

As a feature of the present construction, the multiple position valve means is pressure balanced for easy displacement by the governor assembly to positions controlling the system as above explained. Such a pressure balanced valve construction is disclosed in my copending application, Serial No. 108,658, filed May 8, 1961, now abandoned, for control valve. Two separate valves of this character are most conveniently used in the present control system, one for controlling the starting air, and one for controlling the engine shutdown operation. These two valves are embodied in two valve housings 32 and 33 which are connected to and project laterally from a housing 34 for the governor assembly 21. The engine starting valve is embodied in housing 33. As will be observed, the latter is provided with internal cylindrical walls 36 and 37 defining coaxial valve chambers 38 and 3? on opposite sides of a relatively enlarged center chamber 443. Mounted within these chambers is a valve member 42 having a series of longitudinally spaced piston-like heads 43, 44, 45 and 46 mounted for longitudinal reciprocation on walls 36 and 37 in sealed relation thereto. Heads 43 and 44 are supported on wall 36 with head 44 moving into and out of the center enlarged portion 40; and head 46 and 46 are engaged on wall 37 with head 45 moving into and out of the center chamber 44), the arrangement here used positioning head 45 in the center chamber when head 44 is moved out of the center chamber and vice versa. Elastic rings are provided around the heads 43-46 to provide a close matching and sliding fit with the interior walls 36 and 37. Housing 33 is formed with a plurality of longitudinally spaced passages 51, 52, and 53 which open to the interior bore as ports at wall 36, enlarged chamber 4%, and wall 37 respectively. As will be seen from FIG- URE 1, the pressure supply conduit 29 is here connected to port 53. Port 52 is connected to conduit 17 leading to the pressure responsive valve 14. Port 51 is left open to the atmosphere. With reference to- FIGURE 3, the valve member 42 has an initial or rest position wherein head 45 is moved into the enlarged center chamber 4%, and head 44 is moved into sealed engagement with wall 36. Accordingly, air pressure entering through port 53 may pass head 45 and exit through port 52 to the pressure responsive valve. In this case it will be noted that the air pressure within the housing is applied to heads 46 and 44, thereby creating a pressure balanced condition within the housing. After the engine is started, valve member 42 is moved to the right, as viewed in FI URE 3, moving head 45 into sealed engagement on wall 37 and moving head 44 into the enlarged center chamber 40. In this position of the parts, pressure entering port 53 is applied equally to heads 45 and 46 to continue the balanced condition; and port 52 is vented to the atmosphere through port 51. The outer end of the valve chamber is here closed by a cap 54 which is formed with a vent opening 56 to permit free movement of the valve member within the bore. The provision of the several longitudinally spaced heads 4346 and the valve chambers and passages connected thereto, as illustrated in FIGURES 1 and 3, provide what is termed a balanced valve in which the fluid pressures in the several chambers of the valve are essentially balanced at all times insofar as their application of a displacing force on the valve is concerned. Accordingly, the balanced valve so constructed may be moved longitudinally between its several operating positions with a minimum applied force, thus making it ideally suited for use with the governor assembly 21.

The governor assembly, here illustrated, is of the type produced by Novi Governor Division of Continental Motors Corporation of Novi, Mich., and is more fully disclosed in their Patent 2,250,982. Briefly, however, the governor assembly consists of a shaft 57 journalled for rotation in housing 34 and which projects therefrom and is here fitted with a pulley wheel 58 for connection by belt 19 to an engine driven pulley wheel 59. Secured for rotation with shaft 57 is a cage support 61 for a plurality of governor balls 62 carried by the cage in radial slots for centrifugal movement, as a function of engine speed. These balls are confined by a hood member 63 which normally holds the balls radially inwardly displaced and against a plate-like disc on the cage member, the hood being displaced longitudinally of the shaft as the balls move outwardly under centrifugal force.

The operating connection between the governor assembly 21 and valve member 42 is here effected by a lever 66 pivoted at its lower end by pin 67 journalled in a boss 68 in housing 34, see FIGURES 4 and 5, and being connected medially of its length by pin 69 to one end 71 of valve member 42. As will be seen in FIGURES 3 and 4, valve end 71 is threaded and carries thereon a nut member 72 which is formed with spaced flanges 73 and 74 engageable on opposite sides of pin 69 so that movement of the lever 66 in a clockwise direction, as viewed in FIGURE 4, will be accompanied by a displacement of valve member 42 to the right and contrariwise a displacement of lever 66 in a counterclockwise direction will be accompanied by a displacement of valve member 42 to the left, as viewed in FIGURE 4. If desired, and as here shown, a jam nut 76 may be mounted on valve end 71 for locking nut member 72 in preset position. As will be observed from FIGURE 5, lever 66 is mounted to one side of center, and a second lever 77 is mounted to the other side of center and is similarly and coaxially pivoted by pin 78 extending into a boss 79 provided in the housing in the same manner as lever 66, the two levers 66 and 77 being connected by a top bar or pin 81 for joint oscillation. Displacement of the two levers in a clockwise direction, as viewed in FIG- URES 2 and 4, is here eifected by the governor assembly 21, and a reverse displacement of the levers is effected by a pair of springs 82 and 83 which act upon the cross bar 81. As here shown, levers 66 and 77 carry attached and confronting pins 86 and 87 which are engaged by a flange 88 provided on a collar member 89 journalled on a central hub portion of the hood member 63. As will be observed from FIGURE 2, an increase in speed of rotation of shaft 57 will be accompanied by a radially outward displacement of balls 62 and a displacement of hood member 63 to the right along shaft 57. This displacement will carry flange 88 against pins 86 and 87 and cause a rotary displacement of levers 66 and 67 in a clockwise direction, as viewed in FIGURES 2 and 4, and against the resilient resistance of springs 82 and 83.

The pressure responsive valve 14 here consists of a. valve housing having three axially aligned valve seats 92, 93 and 94 which cooperate with valve members 96, 97 and 98 which are carried for joint movement on a common valve stem 99. As will be seen from FIGURE 1, displacement of valve stem 99 in a downward direction, as seen in this view, will simultaneously move valve member 96 away from seat 92; valve member 97 away from seat 93; and seat valve member 98 on seat 94. The interior construction of the housing is such as to provide an inlet chamber 101 at the inlet side 24 of the housing which communicates with opposite sides of seats 92 and 93 so as to provide a balanced pressure condition across valve members 96 and 97 in their closed seated position. The interior sides of seats 92 and 93 are connected to a discharge chamber 102 at the discharge side 163 of the housing connected to conduit 11; and there is also provided an atmospheric by-pass chamber 104 which leads from chamber 102 to the interior side of seat 94, the exterior side of seat 94 being connected by an atmospheric vent passage 196. Accordingly, when valve stem 99 is depressed, as seen in FIGURE 1, air pressure will be communicated from inlet chamber 101 to discharge chamber 192 for passage to conduit 11 and the starting motor 7 while the atmospheric vent chamber 104 is shut off by seating of valve 98 on seat 94. Upon return movement of the valve stem 99, valve members 96 and 97 will seat thereby shutting ofi air flow to conduit 11 and at the same time valve member 98 moves away from seat 94 so as to thereby open the atmospheric vent chamber 104 and relieve air pressure on the starting motor 7.

Pneumatic operation of valve stem 99, as above explained, is here effected by an actuator which includes a diaphragm 107 mounted at one end of housing 91 within a cap member 108 which defines with the diaphragm 107 a pressure chamber 109 at the outer side of the diaphragm. Cap 168 is formed with an inlet opening 111 to which one end of conduit 17 is connected. The upper end of valve stem 99 is here secured to the center of diaphragm 107 and the stern and diaphragm are urged upwardly, with reference to FIGURE 1, by a spring 112 which is compressed between the diaphragm and the housing so as to constantly urge the diaphragm to a raised position extending into pressure chamber 109. Accordingly, the application of pneumatic pressure from conduit 17 will depress diaphragm 107 against the action of spring 112 to displace valve members 96 and 97 to open position and valve member 98 to closed position, as above explained. When the air pressure in line 17 is relieved, the parts will return to their opposite positions by spring 112.

Air starting valve 28 may, as above noted, be either automatically or manually operated. It may consist, as here shown, of a housing 113 which has an interior valve chamber 114 arranged for receipt of a reciprocating valvemember which moves in chamber 114 between inlet and discharge ports 117 and 118 and between discharge port and an atmospheric vent port 119. Normally, valve member 116 is biased to its position as shown between ports 117 and 118 by spring 121 and may be displaced against this spring by a stem 122 extending from the valve member through one end of the housing for manual or automatic operation. With the parts in their normal spring biased position, the inlet port 117, connected to conduit 27, is sealed off from outlet port 118 which is connected to conduit 29; and outlet port 118 and conduit 29 are communicated with the atmospheric vent port 119. Upon depressing of stem 122, valve member 116 may be moved downwardly, as seen in FIGURE 1, to a position between ports 118 and 119. In this position, air pressure passes through the valve from conduit 27 through port 117 then through the interior chamber 114 and out port 118; and in this position both ports 117 and 118 are sealed off from the vent port 119 by the valve member 116.

Starting Operation When the engine is not running, the governor assembly 21 will be displaced all the way to the left, as viewed in FIGURES 2 and 3, thereby placing valve member 42 in the position illustrated in FIGURE 3 communicating ports 53 and 52. Consequently, depressing of stem 122 of the air starting valve 28 will send air under pressure through conduit 29 through valve member 33 and out port 52 and conduit 17 to the pneumatic actuator chamber 109 of valve member 14. The application of pressure in chamber 109 opens valve members 96 and 97 and closes valve member 98 thereby sending high pressure air from conduit 23 through the valve and conduit 11 to the starting motor to start up the engine. When the engine starts, the governor assembly 21 will move to the right, as viewed in FIGURES 2 and 3, thereby moving valve member 45 into sealed engagement on chamber wall 37 and closing oil communication between ports 52 and 53 thus shutting off the air pressure flow to the pneumatic actuator chamber 189 of valve 14. At the same time, valve member 44 moves into the enlarged center chamber 40 so as to communicate port 52 to atmospheric vent port 51 thereby relieving presure in chamber 109 and permitting valve member 14 to return to closed position under the action of spring 112, thus shutting off the air supply to the starting motor. It is to be noted that this discontinuance of air to the starting motor is controlled solely by the starting up of the engine itself. Continued holding down of stem 122 of air starting valve 28, for example, will be ineffective to get starting air pressure to motor 7 since after the engine has started, there is no communication between ports 52 and 53 in the speed responsive valve unit. Consequently, it is only necessary to hold down stem 122 for a period suiiiciently long to permit starting of the engine. This may be accomplished manually or by a mechanical actuator in turn controlled by some exterior condition such as a power failure where the engine 6 is arranged to run a standby generator. In either event, valve member 28 may be remotely operated and no harm will result from holding valve 22 open for a period longer than it takes to start the engine since the main air supply to the starting motor is automatically shut off upon starting of the engine.

Shutdown System As above noted, the shutdown actuator 12 is also operated by pneumatic pressure, and this is supplied by a companion valve 142 mounted in valve housing 32 and being formed similar to valve member 42 with a series of longitudinally spaced enlarged head portions 143, 144, 145 and 146 corresponding with head portions 43, 44, 45 and 46 of valve member 42.

Heads 143 and 144 are adapted to engage in sealed relation interior chamber wall 136, and heads 145 and 146 are arranged to engage in sealed relation interior chamber wall 137; and heads 144 and 145 are arranged to move alternately into and out of a center enlarged chamber 140. Ports 151, 152 and 153 are provided in casing 32 in the same manner as ports 51, 52, 53 of the first described valve. Valve member 142, however, is displaced further to the left, as viewed in FIGURE 3, than valve 42 in the off condition of the engine 6. In such position, air pressure from conduit 31 connected to port 153 passes out of the valve through port 152 connected to conduit 16, which is in turn connected to the pressure actuated shut-ofi device 12 holding the latter in its cocked position, as above described. Upon removal of air pressure from line 16, device 12 will be actuated, as described below, to shut oif the flow of fuel to the engine.

Valve member 142 is displaced by lever 77 by pin 169 engaging against a collar 174 on valve end 171 in the same manner as described in connection with the first valve member 42, except that collar 174 is initially spaced from pin 169, as shown in FIGURE 3. Consequently, as the motor is started, valve member 142 will not be immediately displaced to the right. Consequently, since collar 174 is set further to the right, as seen in this view, such movement of lever 77 during normal engine speeds does not move head member 145 to interior surface 137 thereby maintaining communication between ports 153 and 152. In accordance with the present invention, displacement of valve member 142 so as to cut off the air pressure to the shut-off device 12 will occur only upon a predetermined over speeding of the engine 6. When this occurs, the governor assembly 21 will move further to the right, as viewed in FIGURE 2, thereby displacing valve member 145 into seated engagement on wall 137 and close ofi the pressure port 153. At the same time, valve head 144 moves off from chamber wall 136 and into the enlarged center chamber thereby communicating port 152 to the atmosphere and releasing the pressure on the actuator 12, through port 151.

Springs 82 and 83 are mounted for applying their resilient force successively. Spring 82 acts alone to resist the initial swing of levers 66 and 77 to displace valve member 42 to position shutting off the air flow to the pressure responsive valve 14. At this point, spring 83 is engaged to resist further movementof the levers, so that the over speed operation of the unit is under the control of both springs. As here shown, springs 82 and 83 are mounted in an elongated housing 181 which is secured to housing 34 and projects therefrom at a position medially between levers 66 and 77 and at the elevation of bar or rod 81, see FIGURES 2, 4 and 5. Mounted for reciprocation in the inner end of tube 181 for movement against pin 81 is a piston-like member 182. Spring 82 is compressed between piston 182 and a movable spring rest 183 carried at the inner end of a pressure adjusting rod 184. The latter is mounted for reciprocation in concentric sleeves 186 and 187 mounted in casing 181. Sleeve 187 is threaded to casing 181 and abuts one end of spring 183 which is supported at its opposite end against an enlargement 188 on sleeve 186. Enlargement 188 is normally supported against a shoulder 189 provided by member 181 but projects internally so as to lie in the path of one end of piston 182 as the latter is displaced outwardly by the lever cross pin 81. In the initial movement of the levers, piston 182 moves out to engage the inner end of enlargement 188 against the resilence 'of spring 82. However, at this point, further movement of piston 182 will pick up the action of spring 83 by displacing the enlargement 188 to the right, as viewed in FIGURE 2. The latter displacement occurs in the present design when over speeding of the engine occurs.

Preferably, to prevent creeping of the parts in operation, displacement of enlargement 188 by piston 182 is her efiected only by snap action. To accomplish this structure a spring pressed detent 191 is mounted in housing 34 for radial displacement into a peripheral groove 192 formed in the enlargement 188. Consequently, in the normal position of the parts, as illustrated in FIG- URE 2, detent 191 engages in groove 192 to hold the enlargement 188 against displacement. However, as the force applied by piston 182 builds up against the end of enlargement 188, a point will be reached when the holding force of detent 191 is overcome and member 180 will be abruptly displaced to the right, as viewed in FIG- URE 2, against the resistance of spring 83. When this occurs, valve member 142 will be displaced to the right, as seen in FIGURE 3, thereby closing off the pressure port 146 and releasing the pressure on actuator 12 to shut down the engine. When engine operation ceases, the governor assembly and other parts will return, to the left, as viewed in FIGURES 2 and 3, under the action of springs 82 and 83. However, it is frequently desirable not to automatically return valve member 142 to operating position since the reason for the over speed condition may be a severe one, and it is best that the engine not be started without checking out and correcting the cause. Accordingly, in the present design, only a single flange 174 is provided for engagement with pin 169 so that the swinging of the levers to the right, as seen in the drawings, will be accompanied by a corresponding movement of valve 142, but that a return movement of the levers will not be accompanied by a corresponding return movement of valve member 142. Rather, valve member 142 will remain in its displaced position preventing operation of the engine. To reset valve 142' it is accordingly necessary to operate a manually displaceable member 193 here mounted at the outer end of valve housing 32 and which may be pushed in, to the left, as seen in FIGURE 3, to reset valve 142 to its original position.

The engine shutdown actuator 12' is here shown of the same type more fully disclosed and claimed in my copending application, Serial No. 103,519, filed April 17, 1961, for Pressure Responsive Safety Control for Internal Combustion Engines. Rod 13 is attached to an arm 202 in turn fastened to shaft 203 for rotation therewith. Also attached to shaft 203 is an arm 204 formed with an enlarged portion 205 having a latching shoulder 206 formed therein. A spring 207 is connected to shaft 203 and is attached to arm 204 and a stop shaft 208 whereby shaft 203 is constantly urged in a counterclockwise direction, as viewed in FIGURE 1, tending to bring arm 204 into abutment with stop shaft 208 and corresponding with the shut-off position of the device. On displacement of lever 202 to its run position, shaft 203 is rotated in a clockwise direction, swinging arm 204 away from stop shaft 208 and to a position whereby shoulder 2'06 rests on an abutmentshoulder on a lever ar-m 211 journalled on a shaft 212. Lever arm 211 is held in the position illustrated cocking arm 202 in run position, by a pin 213 in turn supported by diaphragm 217 against the action of spring 214. Diaphragm 217 is mounted in a pressure chamber 215 having an inlet passage 220 to which conduit 16 is connected. So long as air pressure is present inchamber 215, lever 211 will be rotated to the right, as viewed in FIGURE 1, to hold arm 202 in its cocked run position against the action of spring 214. When, however, pressure fails in chamber 215, spring 214 will displace lever 211 in a counterclockwise direction away from shoulder 206 thereby trtiggering the return movement of arm 202 to shut-01f position by spring 207.

Operation of Shutdown System The engine attendant will first displace arm 202 to its run" position against the action of spring 207. Lever 211 will then automatically move up to engage shoulder 206 and hold arm 202 in its cocked position, this action of lever 211 being under the influence of pneumatic pressure chamber 215 supplied by conduit 16. With reference to FIGURE 3, it will be noted that in the shutotf position of the engine and during its normal operation, pneumatic pressure may pass from conduit 31 through ports 153 and 152 to conduit 16, and this condition will remain so long as the engine does not over speed or start to run away. When the latter condition occurs, the governor assembly 21 will build up force on the spring assembly, illustrated in FIGURE 2, until sufiicient force is built up to cause the release of detent 191, when abrupt and further displacement of valve member 142 will occur moving valve head 145 into engagement with chamber wall 137 and closing 01f the pressure port 153. At the same time, valve head 144 will move into the center enlargement and thereby vent port 152 to the atmospheric port 151, thus collapsing pressure in chamber 215. When the latter action occurs, spring 214 will displace lever 211 away from its supporting position with respect to shoulder 206 and thereby permit spring 207 to rotate arm 202 to shut-off position, thus acting through rod 13 to shut off the fuel supply to the engine.

I claim:

1. A fluid pressure engine start and safety shutdown system comprising:

(a) a normally closed main valve adapted to control a supply of engine starting air from a source to a pneumatic operated engine starting means and a pneumatic valve actuator therefor connected to open said valve;

(12) a pressure responsive engine shutdown actuator adapted for connection to a source of reduced fluid pressure;

((2) a multiple position valve having first, second, and third positions and adapted for connection to said reduced fluid pressure source and being connected to said pneumatic valve actuator, said pressure responsive engine shutdown actuator, and to the atmosphere;

(d) said first valve position establishing communication between said reduced pressure source, said pneumatic valve actuator, and said pressure responsive engine shutdown actuator, said second valve position establishing communication between said pneumatic valve actuator and the atmosphere and maintaining said communication between said reduced pressure source and said pressure responsive engine shutdown actuator, and said third valve position establishing communication between said engine shutdown actuator and the atmosphere and maintaining said communication between said pneumatic actuator and the atmosphere; and

(e) an engine speed responsive actuator adapted for connection to said engine and connected to and displacing said multiple position valve from said first position to said second position when said engine is started and from said second position to said third position when said engine exceeds a predetermined speed.

2. A fluid pressure engine start and safety shutdown system as described in claim 1 wherein said engine speed responsive actuator is a governor assembly and said system includes means providing a snap action movement of said multiple position valve from said second to said third position.

3. A device responsive to the speed of an engine comprising:

(a) a normally closed main valve adapted to control a supply of engine starting air from a source to a pneumatic operated engine starting means and a pneumatic valve actuator therefore connected to open said valve;

(b) a pressure responsive engine shutdown actuator adapted for connection to a reduced fluid pressure source;

(c) a multiple position valve having first, second, and third positions and being adapted for connection to said reduced fluid pressure source, said pneumatic 9 valve actuator, said pressure responsive engine shutdown actuator, and to the atmosphere;

(d) said first valve position establishing communication between said reduced pressure source, said pneumatic actuator and said pressure responsive engine shutdown actuator, said second position establishing communication between said pneumatic actuator and the atmosphere and maintaining said communi cation between said reduced pressure source and said pressure responsive engine shutdown actuator, and said third position establishing communication between said engine shutdown actuator and the atmosphere and maintaining said communication between said pneumatic actuator and the atmosphere;

(e) an engine speed responsive actuator adapted for connection to said engine and connected to and displacing said multiple position valve trom said first position to said second position when said engine is started and from said second position to said third position when said engine exceeds a predetermined speed;

(1) and means providing a snap action movement of said multiple position valve from said second to said third position.

4. A device as described in claim 3 wherein said means include:

(a) a first spring biasing said multiple position valve to said first valve position,

(b) a second spring; and

() means programming the action of said second spring for resisting said valve movement between said second and third positions exclusively.

5. A device responsive to the speed of an engine comprising:

(a) a normally closed main valve adapted to control a supply of engine starting air from a source to a pneumatic operated engine starting means and a pneumatic valve actuator therefore connected to open said valve;

(b) a pressure responsive engine shutdown actuator adapted for connection to a reduced fluid pressure source;

(c) a first multiple port valve including a housing formed with a bore;

(d) a first valve member mounted for reciprocation in said bore;

(e) said housing being formed with a plurality of ports 'ommunicating with said bore in longitudinally- .spaced relation;

(f) said valve being adapted for connection to said reduced fluid pressure source, said pressure-responsive starting air pneumatic valve actuator and to the atmosphere;

(g) said first valve member having a first position for establishing communication between said reduced pressure source and said valve actuator and a second position for establishing communication between said valve actuator and the atmosphere;

(it) a second multiple port valve including a housing formed with a bore;

(i) a second valve member mounted for reciprocation in said bore;

(j) said housing being formed with a plurality of ports communicating with said bore in longidudinallyspaced relation;

(k) said second valve being adapted for connection to a reduced fluid pressure source, said pressure re- 19 ponsive engine shutdown actuator, and to the atposphere;

(I) said second valve member having a first position establishing communication between said reduced pressure source and said shutdown actuator and a second position establishing communication between said actuator and the atmosphere;

(m) a governor assembly adapted for connection to said engine and movable in response to rotation thereof and connected to and displacing said first valve member from said first to second position when said engine is started and said governor being connected to and displacing said second valve member from said first to second position when said engine runs faster than a predetermined speed;

(it) and means providing a snap action movement of said second valve member from its first to its second position.

6. A shutdown device responsive to the speed of an engine comprising:

(a) an overspeed valve including a housing formed with a bore;

(b) a valve member mounted for reciprocation in said bore and having a plurality of relatively enlarged spaced apart heads slidably engageable with the bore Walls;

(0) said housing being formed with a plurality of ports communicating with said bore in longitudinally spaced relation;

(d) a pressure responsive engine shutdown actuator adapted for connection to a source of reduced fluid pressure;

(e) said valve being adapted for connection to said fluid pressure source and said pressure responsive engine shutdown actuator, and to the atmosphere;

(f) said valve member having a first position establishing communication between said pressure source and said shutdown actuator and a second position establishing communication between said actuator and the atmosphere;

(g) said ports and said heads being arranged so that said valve member is in pressure balance in all positions of said member and during movement between first and second positions;

(h) a governor assembly adapted for connection to said engine and movable in response to operation thereof and being connected to said valve member for displacing said member to said second position;

(i) a member detachably connected to and movable with said overspeed valve and displaceable by said governor assembly from a first to a second position;

(i) a spring ball detent releasably holding said member in a first position;

(k) a spring biasing said member to said first position;

(I) said member being moveable by said governor assembly to said second position with a snap action when said rotary speed is above a predetermined speed.

References Cited in the file of this patent UNITED STATES PATENTS 2,714,883 Metzger Aug. 9, 1955 2,931,166 King Apr. 5, 1960 2,960,082 Smith Nov. 15', 1960 FOREIGN PATENTS 532,176 Great Britain Jan. 20, 1941 

1. A FLUID PRESSURE ENGINE START AND SAFETY SHUTDOWN SYSTEM COMPRISING: (A) A NORMALLY CLOSED MAIN VALVE ADAPTED TO CONTROL A SUPPLY OF ENGINE STARTING AIR FROM A SOURCE TO A PNEUMATIC OPERATED ENGINE STARTING MEANS AND A PNEUMATIC VALVE ACTUATOR THEREFOR CONNECTED TO OPEN SAID VALVE; (B) A PRESSURE RESPONSIVE ENGINE SHUTDOWN ACTUATOR ADAPTED FOR CONNECTION TO A SOURCE OF REDUCED FLUID PRESSURE; (C) A MULTIPLE POSITION VALVE HAVING FIRST, SECOND, AND THIRD POSITIONS AND ADAPTED FOR CONNECTION TO SAID REDUCED FLUID PRESSURE SOURCE AND BEING CONNECTED TO SAID PNEUMATIC VALVE ACTUATOR, SAID PRESSURE RESPONSIVE ENGINE SHUTDOWN ACTUATOR, AND TO THE ATMOSPHERE; (D) SAID FIRST VALVE POSITION ESTABLISHING COMMUNICATION BETWEEN SAID REDUCED PRESSURE SOURCE, SAID PNEUMATIC VALVE ACTUATOR, AND SAID PRESSURE RESPONSIVE ENGINE SHUTDOWN ACTUATOR, SAID SECOND VALVE POSITION ESTABLISHING COMMUNICATION BETWEEN SAID PNEUMATIC VALVE ACTUATOR AND THE ATMOSPHERE AND MAINTAINING SAID COMMUNICATION BETWEEN SAID REDUCED PRESSURE SOURCE AND SAID PRESSURE RESPONSIVE ENGINE SHUTDOWN ACTUATOR, AND SAID THIRD VALVE POSITION ESTABLISHING COMMUNICATION BETWEEN SAID ENGINE SHUTDOWN ACTUATOR AND THE ATMOSPHERE AND MAINTAINING SAID COMMUNICATION BETWEEN SAID PNEUMATIC ACTUATOR AND THE ATMOSPHERE; AND (E) AN ENGINE SPEED RESPONSIVE ACTUATOR ADAPTED FOR CONNECTION TO SAID ENGINE AND CONNECTED TO AND DISPLACING SAID MULTIPLE POSITION VALVE FROM SAID FIRST POSITION TO SAID SECOND POSITION WHEN SAID ENGINE IS STARTED AND FROM SAID SECOND POSITION TO SAID THIRD POSITION WHEN SAID ENGINE EXCEEDS A PREDETERMINED SPEED. 